1. Field of the Invention
The present invention relates to a data accessing apparatus and a processing system using the same, and more particularly, to a data accessing apparatus for providing the processing system with a capability of being a power-off status to permit data access from/to its storage media by the other processing system.
2. Description of the Prior Art
Common host system, such as a desktop or laptop type computer, a server, a personal digital assistant (PDA), a portable phone, a digital camera and so on, most of which enable performances of their electronic components, e.g. accessing data from/to a specific built-in or additional-attached storage media, in need of a power-on state when a dedicated power supplier or a battery supplies a system power to the host system. In the other word, the respective electronic components of the host system would be unworkable if the host system is on a power-off state. At this moment, if there is a demand to access data from/to the storage media of the powered-off host system, it is necessary to firstly reboot the host system and then await the initialization and inspection on the host system for an interval time. This invokes very inconvenient for the user who operates to consume the data, hastily.
Presently, a prior data accessing apparatus installed within a host system utilizes an additional system controller to detect whether the host system receives an external serial signal input generated from an external device (e.g. a computer) or not, i.e. whether the host system is electrically connected to the external device or not. As long as the host system is powered off and the system controller detects occurrence of the external serial signal input, the system controller controls a power channel switch of a multiplexer (MUX) to draw a standby power from a power supplier of the powered-off host system and performs a voltage conversion, and thereby supplies the power required for operations of various electronic components of the powered-off host system including, for example, a data storage unit (e.g. a hard disk). Under this manner, the external device could be permitted to access the data from/to the data storage unit of the powered-off host system. Note that even when the host system is on the power-off state, the data storage unit, the prior data accessing apparatus and the related components including the system controller still need to consume the standby power from the power supplier. Such a state where the host system is being conditioned should not be a complete power-off state. Briefly, the prior data accessing apparatus is not capable of satisfying the completely powering-off requirements for some host systems. To implement switches of different power channels and data channels, the prior data accessing apparatus needs to be laid out with more additional elements thereon, e.g. several standby power channels are established to electrically connect all of the elements of the prior data accessing apparatus to the standby power, which can not utilizes most of existent components of the host system.